Fabrication methods of a patterned sapphire substrate and a light-emitting diode

Abstract

A fabricating method for patterned sapphire substrate is provided. The fabricating method includes the following processes. First, a sapphire substrate is provided, and a mask layer is formed on the sapphire substrate, wherein the mask layer with appropriate pattern exposes a part of the sapphire substrate. Then, a wet etching process is performed to remove the exposed part of the sapphire substrate, wherein an etchant in the wet etching process includes sulfuric acid and the mixture of the sulfuric acid and the phosphoric acid. Next, the mask layer is removed to form the patterned sapphire substrate. Further, a fabricating method for light-emitting diode is provided.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the priority benefit of Taiwan application serial no. 95134409, filed on Sep. 18, 2006. All disclosure of the Taiwan application is incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a fabricating method for a light-emitting device, and more particularly, to a fabricating method for a patterned sapphire substrate to grow GaN layers.[0004]2. Description of Related Art[0005]The light-emitting diode (LED) has been mainly used in various traffic lights, the electronic products installed in cars, the backlight module of the liquid crystal display, and the general illumination devices. The conventional materials for fabricating an LED capable of emitting visible light include a group of III-V compounds consisting of the AlGaInP and GaN. The AlGaInP is used in the LED emitting red, orange and yellow light; the GaN is used in the LED emitting gre...

AI Technical Summary

Benefits of technology

[0008]The present invention is directed to a fabricating method for a patterned sapphire substrate to simplify the foresaid etching process, decrease the cost of the etching process, and increase the speed of the etching process.

[0009]The present invention is further directed to a fabricating method for an LED to increase the power of outputting light and the external quantum efficiency of the LED.

[0018]The present invention can simplify the process for fabricating the patterned sapphire substrate, especially reduce the cost of etching process and increase the etching speed.

Problems solved by technology

However, the mismatch between the lattice of the sapphire and the lattice of the GaN crystal results in the high density of threading dislocations of the GaN crystal in the light-emitting diode.

The threading dislocations reduce the power of light and lifetime and also increase the current leakage.

However, because the sapphire has high chemical stability and high hardness, it is difficult performing the general etching process to form the patterns on the sapphire substrate.

For example, the dry etching process has more parameters, low etching speed, high cost and also inherently damages and strains to the substrate; while, the laser assisted etching is not suitable for forming complicated patterns.

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